Kestrel响应为413 Payload Too Large，但HttpSys响应为通用500 Internal Server Error响应.我假设您使用第二个.在这种情况下，您可以实现异常处理中间件来处理这种情况:

Kestrel responds with a 413 Payload Too Large response, but HttpSys responds with a generic 500 Internal Server Error response. I assume you use the second one. In this case you can implement Exception handling middelware to handle this case:

public class ExceptionMiddleware
{
    private readonly RequestDelegate _next;

    public ExceptionMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext httpContext)
    {
        try
        {
            await _next(httpContext);
        }
        catch (Exception ex)
        {
            HandleExceptionAsync(httpContext, ex);
        }
    }

    private static void HandleExceptionAsync(HttpContext context, Exception exception)
    {
        if (exception is BadHttpRequestException badRequestException && badRequestException.Message == "Request body too large.")
        {
            context.Response.StatusCode = (int) HttpStatusCode.RequestEntityTooLarge;
        }
    }
}

并在Startup.cs中的"Configure"中注册它:

And register it in Configure in Startup.cs:

public void Configure(IApplicationBuilder app)
{
    ...
    app.UseMiddleware<ExceptionMiddleware>();
    ...
}

您也可以使用异常过滤器